Sylvain Lecomte

A cooperative reservation protocol for parking spaces in vehicular ad hoc networks

By exchanging events in a vehicular ad hoc network, drivers can receive interesting information while driving. For example, they can be informed of available parking spaces in their vicinity. Obviously, a suitable protocol is needed to disseminate the events efficiently within the area where they are relevant. Moreover, in such a competitive context where each vehicle may be interested in the resource, it is crucial not to broadcast that resource to each driver in the vicinity. Otherwise, those drivers would waste time trying to reach a parking space and only one of them would be satisfied, which would lead to a poor satisfaction in the system. To solve this problem, we detail in this paper a reservation protocol that efficiently allocates parking spaces in vehicular ad hoc networks and avoids the competition among the vehicles. We have integrated our protocol within VESPA, a system designed for vehicles to share information in VANETs.

Sharing with caution: Managing parking spaces in vehicular networks

By exchanging events in a vehicular ad hoc network VANET, drivers can receive interesting information while driving. For example, they can be informed of available parking spaces in their vicinity. A suitable protocol is needed to disseminate the events efficiently within the area where they are relevant. Moreover, in such a competitive context where each vehicle may be interested in a resource, it is crucial not to communicate that resource to each driver in the vicinity. Otherwise, those drivers would waste time trying to reach a parking space and only one of them would be fulfilled, which would lead to a poor satisfaction in the system. To solve this problem, we detail in this paper a reservation protocol that efficiently allocates parking spaces in vehicular ad hoc networks and avoids the competition among the vehicles. We have integrated our protocol within VESPA, a system that we have designed for vehicles to share information in VANETs. An experimental evaluation is provided, which proves the usefulness and benefits of our reservation protocol in both parking lots and urban scenarios. Besides, we present an in-depth study of the state of the art on this topic, that shows the interest and the originality of our approach.

Component based Framework to Create Mobile Cross-platform Applications

Abstract Smartphones provide a set of native functionalities and another set of functionalities available through third-party applications. The emergence of more and more actors, without standards to provide their devices or OS, stops the cross-platform development. Indeed, a developer would have to learn many programmatic languages and create many user interfaces for many devices. To resolve this problem, several solutions often consist in the creation of a com- mon SDK to only write the application once. Then, the application code is translated in native code for each target platform. In this paper, we propose a solution based on a component model. A set of configurable components is implemented for the targeted platforms. A component will have a common interface independent from the host OS. Finally, a new language will offer developers a single instruction call to any component through its interface. This instruction is common on any platforms to simplify the implementation of a cross-platform application.

Hybrid peer-to-peer model in proximity applications

The recent emergence of handheld devices and wireless networks has implied an exponential increase of terminals users. So, today, service providers have to propose new applications adapted to mobile environments. In this paper, we propose and describe a new class of distributed applications called the proximity applications. In such applications, two or more handheld devices, physically close to each other, can communicate and exchange data in a secure way. Proximity applications rely on the use of both different mobile devices and heterogeneous wireless networks. Thus, these applications need a high degree of flexibility, for an easy and rapid application development. In this context, our purpose is to study the interest of the Hybrid Peer-To-Peer (P2P) architecture model use specially for the extensibility, the fault-tolerance management and the scalability of proximity applications. Moreover, thanks to this model, proximity applications can easily face to the heterogeneity of devices and networks.

Design guidelines for quality of service support in Optimized Link State Routing-based mobile ad hoc networks

The proposals for quality of service in mobile ad hoc networks have focused on adding QoS mechanisms in best-effort routing protocols while keeping the same assumptions regarding both the network representation and the routing protocol design. Most of the solutions concentrate the algorithmic effort on QoS route computation and relax the constraint of optimizing flooding, which has, however, a great impact on resource consumption. The goal of this paper is to present guidelines that allow the design of efficient solutions accurately presented and easily comparable with each other. We first define the QoS metric as an abstraction that can be instantiated for any kind of metric, and we propose a MANET representation that integrates this abstraction into the definition of the network graph and properties. Using these concepts, while flooding optimization and QoS-aware MPR selection have usually been performed separately, we then propose a formalism that unifies MPR selection in such a way that both objectives are achieved simultaneously in a single selection. Finally, we propose a heuristic that provides an efficient solution for this problem while allowing us to control the trade-off between both objectives. Evaluations carried out on network graphs considering different spatial distributions of nodes show that our heuristic outperforms existing heuristics.

Adaptive query processing in mobile environment

These last years, the evolution of nomadic terminals and mobile networks has yield to the development of the ubiquitous computing. In this context, actual query evaluation and optimization techniques in distributed databases based on the use of a global schema and a cost model are no more relevant. Furthermore, a query processor deployed in this type of environment must face a significant heterogeneity, in particular mobile terminals, communication networks and different data sources. In order to cope with this heterogeneity, such service should have the capability to adapt itself dynamically. In this paper, we describe the problems related to query processing in mobile environment and the needs for adaptability.

Performance Evaluation of Multimedia Applications over an OLSR-Based Mobile Ad Hoc Network Using OPNET

Mobile ad hoc network architecture allows cheap and easy deployment of network services almost anywhere and at anytime. Besides Internet access which is a best-effort service, multimedia applications are the most requested. They usually impose stringent quality of service constraints in terms of metrics including bandwidth, end-to-end delay, jitter and loss rate. In this paper, we evaluate the performance of a QoS extension of the OLSR protocol on voice communication using the OPNET simulator. The network model can represent various locations like railway stations, Campus University or traffic jam. We describe the performance end users involved in voice communication session can expect, even in presence of other traffics, like file transfer between other users in the same network.

Multi-scale query processing in vehicular networks

In the last decade, a number of wireless and small-sized devices (e.g., PDAs, smartphones, sensors, laptops, etc.) with increasing computing capabilities have appeared in the market at very affordable costs. These devices have started to be embedded in modern cars in the form of on-board computers, GPS navigators, or even multimedia centers. Thus, the vehicles can carry useful information, acting as data sources for other vehicles. Recently, some works have addressed the problem of processing queries in such highly dynamic vehicular networks in order to share information between drivers. The proposed query processing techniques usually rely on a push model. Hence, each vehicle receives data from its neighbors and decides whether they are relevant enough to be stored in a local data cache. Then, the data may be used by a query processor to retrieve relevant data for the driver. In this paper, we look at the problem from a broader perspective and discuss the interest of multi-scale query processing techniques in such context. The goal of such techniques is to exploit, at the mobile device’s level, different access modes (e.g., push, pull) and various data sources (e.g., data cached locally, data stored by vehicles nearby, remote Web services, etc.) to provide the users with results for their queries. We highlight the most important challenges and outline some possible approaches. We also present a prototype of a first query evaluator developed using the Microsoft LINQ API.

A context aware framework for services management in the transportation domain

The transportation domain brings particular needs dealing with the specificities of the environment (highly mobile, distributed, unstable network connection, …). In this paper, we propose a dynamic adaptable framework responding to the needs of transportations applicative services. Among the most important services we can name positioning, time or communication capabilities. To achieve both this flexibility and automate context adaptation, we rely on a Service Oriented architecture and experiment our proposition on the inter-vehicular communication system, VESPA. This framework is based on the use of context informations for the transportation domain.

A framework for mobile and context-aware applications applied to vehicular social networks

The notion of context has become very important in computer science, especially when users are highly mobile. In a short period of time the environment changes; communication networks can become available or unavailable, user communities can appear or disappear, etc. The work presented in this paper focuses on the transportation domain and more particularly on applications which accompany and assist the user in transportation activities (e.g., driving, visiting a city, etc.) through the use of ad hoc social networks. We present a case study related to the VESPA system, designed to help drivers by providing them with diverse information (e.g., traffic information, available parking spaces, etc.); we show how the framework we propose can help the system deal with context issues. In the last part, we analyze different mechanisms of changing application behavior through the use of services, an important step towards making our devices reactive to new situations.